Why do we make mistakes in the morphological interpretation of blood slides and how can we improve?
1Clinical Haematology, Manchester Royal Infirmary, Manchester, United Kingdom
Assessment of blood film morphology remains a primary diagnostic method in haematology. However the range of cellular abnormalities in haematological disease can be highly complex. We all accept that errors of interpretation may arise from insufficient care or knowledge, however there are also other more hidden mechanisms that are equally or more important: Knowingly or unknowingly, we all adopt strategies that help us simplify and process the complex visual data we observe on blood films, and these allow us to arrive at a decision regarding the likely pathological process. This "heuristic approach" can be highly effective permitting rapid and accurate assessments of complex combinations of features. However it is recognised in many fields of medicine that these same processes may lead us unwittingly to make quite serious errors. Using data from the UK NEQAS(H) digital CPD scheme, we have analysed the processes used by participants arriving either at correct or incorrect morphological diagnoses. The results reveal how the heuristic processes we employ to help us in morphological interpretation are also a major source of misinterpretation through processes such as anchoring, premature completion of survey, framing effects and multiple alternatives bias. Avoiding such errors requires individuals to be aware of the sources of error, and to use of specific strategies to avoid them, this can be aided also by the appropriate use of decision support mechanisms, and by standardised approaches to nomenclature and grading such as that recently proposed by the ICSH.